Window hinge

ABSTRACT

A friction window hinge comprises a frame plate ( 15 ) for attachment to the fixed window frame ( 12 ), a vent plate ( 27 ) for attachment to the movable window vent ( 11 ), and a separate curved link ( 19 ) which extends between the plates and is slideably engageable with correspondingly curved guide tracks ( 17, 28 ) on both of the plates. In the open position the curved link ( 19 ) is extended between the plates ( 15, 27 ) to support the window vent, while in the closed position the plates are brought into overlying relation with the link retracted between them. The arrangement allows the vent to be swung to the fully open position without the hinged side of the vent significantly obstmcting access through the aperture in the fixed frame.

The invention relates to hinges and in particular to friction hinges forwindows,

A common friction hinge for aluminium or UPVC windows comprises alinkage having a track for fitting to the fixed window frame, a vent armfor fitting to the movable window vent, a slider slideable along thetrack, a link pivotally connected at one end to the slider and at itsother end to the vent arm, and a control arm pivotally connected at oneend to the track and at its other end to the vent arm. The linkarrangement is such that the vent arm is movable between a closedposition where it overlies the track and an open position where itextends at an angle to the track, such movement being accompanied byfrictionally restrained movement of the slider along the track.

Normally, two such hinges are provided at opposite sides of the windowand the geometry of the hinges is such that as the window vent pivots onthe hinges the effective pivot axis of the vent is spaced from the fixedwindow frame. Accordingly, as the window opens, the frame member of thewindow vent which is nearest the hinge axis moves inwardly, partlyacross the window opening, with respect to the adjacent fixed framemember.

This arrangement has the advantage that, when the window is fully open,the person inside the building has access to both sides of the vent forcleaning purposes. However, the movement of the vent frame member partlyacross the window opening, and away from the adjacent fixed frame memberhas the effect of reducing the size of the main window opening in orderto provide a narrow opening to the other side of the vent frame memberfor access to the outer surface of the vent.

For safety reasons, government regulations may specify minimumdimensions for the access aperture provided by a window when in a fullyopened condition. However, aluminium and UPVC framed window assembliesare commonly provided in only a comparatively limited number ofdimensions, partly for aesthetic reasons, but mainly because of theadvantages provided by standardisation of window dimensions. Suchstandardisation reduces costs and facilitates the installation ofwindows in new buildings as well as their subsequent replacement.Standardisation also facilitates the manufacture and supply of windowaccessories which may, again, be of a limited number of standarddimensions.

The situation may, however, arise where a window assembly of a standarddimension, and having friction hinges of the kind referred to above, maynot provide an access aperture, when fully open, which is sufficientlylarge to comply with prevailing regulations. In order to meet thisproblem, manufacturers of friction link hinges of the kind describedabove may supply a modified “access” hinge where certain links of thehinge may be disengaged from one another to allow wider than normalopening of the window in an emergency. However, such hinges are usuallymore complex in structure than the standard hinges and more costly tomanufacture. Also, in an emergency a person wishing to increase thewindow opening in order to climb through it must be familiar with themanner in which the hinges may be disengaged to increase the size of theopening, and this may not always be the case. Also, there may be a riskof the hinges becoming accidentally disengaged during normal use, whichmay be undesirable.

Theoretically, the problem could be solved by mounting the window ventto the fixed frame by traditional butt hinges where the adjacent framemembers of the vent and fixed frame remain close to one another as thewindow is opened. However, it is not practically possible to fittraditional butt hinges to aluminium and UPVC window assemblies of thekinds now commonly in use, due to the configuration of the extrudedframe members which are used in such assemblies.

The present invention sets out to provide an improved form of windowhinge which may provide, when the window is fully opened, an accessaperture through the window which is equivalent to, or only slightlyless than, the full size of the aperture in the fixed window frame, suchhinge being particularly suitable for use with aluminium and UPVC framedwindow assemblies.

According to the invention there is provided a window hinge comprising afirst guide having means for attachment to a fixed window frame, asecond guide having means for attachment to a movable window vent, and alink which is engageable with both said guides and is slideablerelatively to each guide.

Preferably the link comprises a single substantially rigid element, butthe invention does not exclude arrangements where the link is formed intwo or more relatively movable parts so as to be extensible. Forexample, the parts may be longitudinally slideable with respect to oneanother.

At least one of said guides, and preferably each said guide, comprises atrack along which the link slides. Preferably the orientation of thelink relative to the guide is determined by its position along saidtrack.

The track may be curved, e.g. it may be part-circular. The link mayfrictionally engage the track so as to provide some frictional restraintto opening and closing of the window vent, in use, provided that thelink can slide smoothly and without jamming. Preferably the link isformed from metal, but it might also be formed from resilient material,such as a resilient plastics. However, for greater strength a metal linkis preferred.

Preferably stop means are provided between the link and the guide orguides to limit the relative sliding movement between the link and theguide or guides in at least one direction. Said means may compriseinter-engageable abutments on the link and guide or guides.

The track may comprise two generally parallel spaced guide surfacesbetween which at least a part of the link is slideably received. Forexample, the guide surfaces may comprise spaced grooves directedinwardly towards one another and engageable respectively with spacedoutwardly directed flanges formed on the link.

In the case where a track comprising spaced flanges is formed on eachguide, the link may be formed, at each side thereof, with a pair ofspaced parallel outwardly directed flanges for engagement within thetrack grooves of the first and second guides respectively.

Each guide may comprise a base plate, each groove on the guide beingprovided by a generally L-sectioned rail upstanding from the base plate.

The following is a more detailed description of a preferred embodimentof the invention, by way of example, reference being made to theaccompanying drawings in which:

FIG. 1 is a diagrammatic view from above of a friction hinge inaccordance with the present invention, the hinge being shown in the openposition,

FIG. 2 is a view from above of the frame plate of the hinge,

FIG. 3 is a perspective view of the curved link of the hinge (showninverted),

FIG. 4 is a top view of the curved link,

FIG. 5 is an underside view of the curved link,

FIG. 6 is a perspective view of the hinge in the open position, seenfrom above, and

FIG. 7 is a perspective view of the hinge in the open position, seenfrom below.

Referring to FIG. 1: two hinges according to the present invention mounta rectangular window vent 11 to the side of a corresponding rectangularfixed window frame 12. The vent is side hung, that is to say it issupported by upper and lower hinges disposed at the upper and lower endsof a vertical side frame member 13 of the fixed window frame 12,although the hinges may also be used in top hung arrangements. FIG. 1 isa view from above of the lower hinge 14 with the vent 11 in the fully90° open position. The upper hinge (not shown) is a mirror image of thelower hinge 14.

The frame plate 15 of the lower hinge 14 is screwed to the horizontalbottom frame member 16 of the fixed frame 12 adjacent the corner betweenthe bottom frame member 16 and the vertical side frame member 13.

The frame plate 15, which may be die cast from suitable metal, such as azinc alloy, is formed with two parallel part-circular flanges 17. Asbest seen in FIG. 6 the flanges 17 are of inverted L-shape incross-section so as to provide inwardly facing grooves 18 between theflanges 17 and the frame plate 15.

A curved link 19, which also may be die cast from a zinc alloy,slideably engages the flanges 17, the flanges 17 and the link 19 beingof corresponding radii of curvature. As may be seen from FIG. 3, thelink 19 has a central longitudinal web 20 the opposite side edges ofwhich are integrally formed with C-sectioned formations to provide upperoutwardly projecting flanges 21 and spaced parallel lower flanges 22.(The link 19 is shown inverted in FIG. 3.) In FIGS. 1 and 6, the flanges22 of the link 19 are lowermost and are slideably received in thegrooves 18 on the frame plate 15. The underside of the link 19 is formedwith a central longitudinal groove 23, which slides over an abutment 26(see FIGS. 1 and 2) which upstands from the frame plate 15 between theouter ends of the flanges 17 on the plate.

In order to limit the outward sliding movement of the link 19 along theflanges 17, the groove 23 in the underside of the link 19 is closed atone end, as best seen in FIG. 5, so as to provide an end abutmentsurface 25 which engages with the upstanding projection 26 integrallyformed on the frame plate 15.

The link 19 also slideably engages guide flanges on the underside of adie cast metal vent plate 27 which is screwed to the underside of thelower horizontal rail of the vent frame 11. The construction of the ventplate 27 is best seen in FIG. 7 which shows the underside of the ventplate 27.

As may be seen from FIG. 7, the underside of the vent plate 27 isintegrally formed with spaced curved L-sectioned flanges 28 which are ofsimilar cross-section to he flanges 17 on the frame plate 15. In thiscase the upper side flanges 21 of the link 19 engage within the inwardlyfacing grooves provided by the flanges 28 on the underside of the ventplate 27. Again, as may best be seen from FIG. 4, one end of the uppergroove 29 in the link 19 is closed to provide an end abutment surface 30which engages an abutment 32 on the vent plate 27 (see FIG. 6), betweenthe flanges 28, to limit the sliding movement of the link 19 withrespect to the vent plate 27 and prevent it becoming detached from thevent plate.

In order to assemble the three components of the hinge, the link 19 isfirst connected to the lower frame plate 15 by sliding the flanges 22 ofthe link beneath the flanges 17 of the frame plate 15. The open end ofthe groove 23 in the underside of the link 19 slides over the abutment26 on the frame plate 15 until the closed end 25 of the groove strikesthe abutment 26. The link 19 is then in the position shown in FIG. 1.

In order to prevent the link being fitted to the frame plate 15 in theinverted orientation, the abutment 26 is formed with a smallerupstanding abutment 26 a (see FIG. 2) over which slides a narrowergroove 23 a (see FIG. 5) formed in the bottom wall of the groove 23. Thegroove 29 on the upper side link 19 does not have such a smallerauxiliary groove in its bottom wall. Consequently, if an attempt is madeto introduce the link 19 between the flanges 17 in an invertedorientation, i.e. with the flanges 21 lowermost, the groove 29 willbegin to slide over the abutment 26 but it will not be able to movefurther than the auxiliary abutment 26 a since that abutment will beengaged by the leading end of the link, thus preventing the link beingmoved to the position shown in FIG. 1.

After the link 19 has been correctly fitted to the frame plate 15, thevent plate 27 is connected to the link 19 by passing the flanges 28 onthe underside of the vent plate 27 beneath the flanges 21 on the link,the vent plate 27 being slid along the link 19 (clockwise in FIG. 1)until the abutment 32 on the underside of the vent plate 27 engages theclosed end 30 of the groove 29 in the link, in the position shown inFIG. 1.

Referring again to FIG. 1, the window vent 11 is thus supported by thecurved sliding links 19 of the lower and upper hinges which permit thevent 11 to swing outwardly from the fixed frame 12 to the open positionshown in FIG. 1. The effective pivot axis of the hinges, indicated at 33in FIG. 1, is defined by the common centre of curvature of the flanges17, the link 19 and the flanges 28.

As may be seen from FIG. 1, the geometry of the hinges is such that thevent 11 overlaps by only a small amount the aperture defined by theframe members 13 of the fixed frame when the window vent is in the fullyopen position, thus providing an access aperture which is only veryslightly narrower than the aperture in the fixed frame 12. This enablesthe access aperture required by regulations to be achieved with standardsizes of fixed window frame. When the window is in the closed position,with the vent 11 lying within the fixed frame 12, the sash plate 27overlies the frame plate 15 with the link 19 between them.

The end of the frame plate 15 nearest the pivot point 33 is integrallyformed with an upstanding block 34 which is of generally triangularform, having a convexly curved edge 35 which fits within a concavelycurved edge surface 36 on the vent plate 27 when the window vent isclosed and the plate 27 overlies the plate 15. The purpose of the block34 is to prevent the insertion of a screwdriver, jemmy or similarimplement between the two plates 15 and 27 from outside the window forthe purpose of breaking the hinge and thereby being able to obtainunauthorized entry through the window.

Also, the frame plate 15 is formed with an arcuate upstanding rib 37which is centred on the pivot axis 33 of the hinge. As the window ventis moved into the closed position, the rib 37 slides along a groove 38formed in the underside of the vent plate 27. When the window is fullyclosed, and the vent plate 27 overlies the frame plate 15, theupstanding rib 37 on the frame plate lies between two downwardlyprojecting ribs 39 integrally formed on the underside of the vent plate27, on opposite sides of the groove 38. The location of the rib 37between the ribs 39 provides resistance to attempts to break the hingeby trying to lever the closed vent away from the upright 13 i.e. to theleft in FIG. 1.

In order to provide additional security and strength when the windowvent is open, an adjustable stay may be provided extending from theupper horizontal member of the vent to the upper horizontal member ofthe fixed frame. For example, one end of the stay may be pivotablyconnected to the vent, the opposite end of the stay carrying a sliderwhich is slideable along a track mounted on the fixed frame member. Forexample, the track may be in the form of a channel-shaped member alongwhich is slideable a friction pad to which the end of the stay isconnected. Means such as a screw device may be provided on the sliderfor engagement with the track in order to vary the resistance to slidingof the slider along the track and/or to lock the slider in a desiredposition along the track so as to hold the window open at a desiredangle. There may be mounted on the track a disengageable catch which isnormally engageable by the slider to limit the angle of opening of thewindow vent. Release of the catch allows the slider to travel furtheralong the track so that the window may be fully opened when required.The catch may be of the child-proof type in order to prevent a childfrom opening the window beyond a predetermined small amount, for safetyreasons.

Although the adjustable stay could be mounted at the bottom of thewindow if it includes a child-proof catch, positioning at the top of thewindow is preferred. This not only gives better access through thewindow opening in an emergency, but the stay then also acts as a safetydevice, should the upper hinge break, since the top of the window ventwould then remain attached to the adjustable stay instead of topplingover and breaking free from the fixed frame.

In order to increase the frictional engagement between the link 19 andthe flanges 17 and 28, the link 19 could be formed with a slightlongitudinal twist. Bumps might also be formed in the surface of thelink. Alternatively or additionally, there may be received in the web 20of the link 29 a grub screw which bears against a small rectangularfriction pad which is received in a rectangular recess on one side ofthe web 20 so that by turning the grub screw the pressure on thefriction pad against the adjacent surface of the frame plate 15 or ventplate 27 may be adjusted.

In order to facilitate the assembly of the three parts 15, 19, 17 ofeach hinge, each face of the link 19 could be integrally formed with asmall spring leg which snaps over a small abutment on the frame plate orvent plate as the link is first introduced into the flanges on theplate. The link 19 is thereby retained in engagement with the frameplate and vent plate so that its sliding movement is limited to movementbetween the abutments 26 and 32 and the small abutments with which thesprung legs engage.

As previously mentioned, the plates 15 and 27, and the link 19, may bedie cast from metal, for example from a zinc alloy. In this case, theouter surface of the link 19 may be copper plated and then nickel platedfor additional strength and smoothness of operation. Preferably theouter edges of the plates 15 and 27 in the vicinity of the abutments 26and 32 respectively are smoothed to prevent these edges digging into thesurface of the link 19 as the hinge is operated. If the edges on eitherplate were to dig into the surface of the link any further torqueapplied to the vent, in an attempt to close it, could result in damageand even fracture of the link and it is therefore important that thelink 19 slides smoothly with respect to both the frame plate 15 and thevent plate 27.

Instead of the link and the two plates 15 and 27 being die cast, asdescribed above, the link might be moulded, for example from a plasticsmaterial such as acetal resin. The invention is not limited to thecomponents being formed from any particular material or manufactured byany particular process.

The hinge construction in accordance with the present invention and asdescribed above may not only be stronger than the multi-link frictionhinges of the kind previously described, but may also be cheaper tomanufacture, since it comprises fewer parts and involves much lessassembly work than conventional friction hinges.

Although the example shown has only a single one-piece link connectedbetween the vent plate and frame plate, arrangements are also possiblewhere the link comprises two or more extensible parts, for example twoor more parts which are in slideable engagement with one another. Sucharrangement may be advantageous where only limited space is available toreceive the links when the window is in the closed position.

What is claimed is:
 1. A window hinge comprising a first guide havingmeans for attachment to a fixed window frame, a second guide havingmeans for attachment to a movable window vent, and a link which isengageable with both said guides and is slidable relatively to eachguide, wherein each guide is carried on a respective base plate which issubstantially co-planar with the guide and extends laterally thereof,which base plates are substantially parallel to one another and moveinto overlying relationship to one another when the hinge is brought toits closed position.
 2. A window hinge according to claim 1, wherein thebase plates are provided with interengageable formations whichinterengage, when the base plates are in overlying relation, in a mannerto restrain movement of one base plate relative to the other in adirection away from an effective pivot axis of the hinge.
 3. A windowhinge according to claim 2, wherein said interengageable formationscomprise a first rib which extends from one base plate towards the otherbase plate and is interengagable with a second rib which extends fromsaid other base plate towards said one base plate.
 4. A window hingeaccording to claim 3, wherein the rib on one base plate projects betweentwo spaced ribs on the other base plate, when the base plates are inoverlying relation.
 5. A window hinge according to claim 3, wherein saidribs are part-circular and concentric with the effective pivot axis ofthe hinge.
 6. A window hinge according to claim 1, wherein at least oneof the base plates is provided with a projecting formation which isslideable along a groove formed in the other base plate, said groovebeing concentric with an effective pivot axis of the hinge.
 7. A windowhinge according to claim 6, wherein said projecting formation is apart-circular rib which is concentric with the effective pivot axis ofthe hinge.
 8. A window hinge according to claim 1, wherein at least oneof the base plates is provided with a structure which extends across aregion of the peripheral edge of the other base plate, when the baseplates are in overlying relation, in a manner to prevent insertion of animplement between the base plates in said peripheral region.
 9. A windowhinge according to claim 1, wherein the link comprises a singlesubstantially rigid element.
 10. A window hinge according to claim 1,wherein each of said guides comprises a track along which the linkslides.
 11. A window hinge according to claim 10, wherein each track ispart-circular.
 12. A window hinge according to claim 10, wherein thelink frictionally engages each track so as to provide some frictionalrestraint to opening and closing of the window vent, in use.
 13. Awindow hinge according to claim 1, wherein the link and both guides areformed from metal.
 14. A window hinge according to claim 13, wherein thelink in nickel plated.
 15. A window hinge according to claim 14, whereinthe link is nickel plated on top of copper plating.
 16. A window hingeaccording to claim 1, wherein the link and/or at least one of the guidesis formed from resilient material.
 17. A window hinge according to claim1, wherein stop means are provided between the link and at least one ofsaid guides to limit the relative sliding movement between the link andthe guide in at least one direction.
 18. A window hinge according toclaim 17, wherein said stop means comprise projections on the guideswhich are slidable along respective closed-ended grooves in the link.